Year Number 1996 0.717076897621155 1998 0.728511989116669 2000 0.713235020637512 2002 0.792559921741486 2003 0.851720035076141 2004 0.893765926361084 2005 0.819073557853699 2006 0.77465146780014 2007 0.771330535411835 2008 0.795972287654877 2009 0.693532228469849 2010 0.911838114261627 2011 0.964122116565704 2012 0.98025369644165 2013 0.970303058624268 2014 0.913897812366486 2015 0.961817383766174 2016 0.975613653659821 2017 0.981489479541779 2018 1.13303458690643 2019 1.0513995885849 2020 1.00336503982544 2021 1.00239610671997 2022 1.03453397750854